Relative Performance of CAS2 vs. CAS3

Crucial Technology PC100 SDRAM DIMMs each have a letter near the end of the module's part number which designates the timings of the module. The following chart shows the different timings for each type of memory:

CAS Latency tRP tRCD
A 3 3 3
B 3 2 3
C 3 2 2
E 2 2 2

These different options are all equally compatible when used on a 100MHz bus, but if you use all of one of the above part type in your PC there is a small performance difference. The performance difference between an A and a B is 0.7% (the B being the faster of the 2). The difference between the B and the C is 0.1%, and the difference between the C and the E is 0.5% (the cumulative difference between the A and the E is 1.3%).

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